A multistate open robust design: population dynamics, reproductive effort, and phenology of sea turtles from tagging data

2018 ◽  
Vol 89 (1) ◽  
pp. e01329 ◽  
Author(s):  
William L. Kendall ◽  
Seth Stapleton ◽  
Gary C. White ◽  
James I. Richardson ◽  
Kristen N. Pearson ◽  
...  
2006 ◽  
Vol 84 (8) ◽  
pp. 1210-1215 ◽  
Author(s):  
Pei-Jen L. Shaner

Food availability often drives consumer population dynamics. However, food availability may also influence capture probability, which if not accounted for may create bias in estimating consumer abundance and confound the effects of food availability on consumer population dynamics. This study compared two commonly used abundance indices (minimum number alive (MNA) and number of animals captured per night per grid) with an abundance estimator based on robust design model as applied to the white-footed mouse ( Peromyscus leucopus (Rafinesque, 1818)) in food supplementation experiments. MNA consistently generated abundance estimates similar to the robust design model, regardless of food supplementation. The number of animals captured per night per grid, however, consistently generated lower abundance estimates compared with MNA and the robust design model. Nevertheless, the correlations between abundance estimates from MNA, number of animals captured, and robust design model were not influenced by food supplementation. This study demonstrated that food supplementation is not likely to create bias among these different measures of abundance. Therefore, there is a great potential for conducting meta-analysis of food supplementation effect on consumer population dynamics (particularly in small mammals) across studies using different abundance indices and estimators.


Author(s):  
Andrés Valenzuela‐Sánchez ◽  
Claudio Azat ◽  
Andrew A. Cunningham ◽  
Soledad Delgado ◽  
Leonardo D. Bacigalupe ◽  
...  

2021 ◽  
Vol 657 ◽  
pp. 191-207
Author(s):  
MD Ramirez ◽  
T Popovska ◽  
EA Babcock

Knowledge of sea turtle demographic rates is central to modeling their population dynamics, but few studies have quantitatively synthesized existing data globally. Here, we used a Bayesian hierarchical model to conduct a meta-analysis of published von Bertalanffy growth curve parameters (growth coefficient, K; asymptotic length, L∞) for chelonid sea turtles. We identified 34 studies for 5 of 6 extant chelonids that met minimum selection criteria. We implemented a suite of models that included a multivariate normal likelihood on the log-transformed values of the 2 parameters to evaluate the influence of species, population (regional management unit, RMU), parameter estimation method (mark-recapture, skeletochronology, length-frequency analysis), latitude, and sampled body size range (all sizes, no large, no small, no large or small) on growth parameter estimates. According to information criteria, the best model included a random effect of species. The second best model also included latitude as a fixed effect, but RMU, parameter estimation method, latitude, and sampled body size ultimately did not strongly influence the means or variances of K and L∞ among studies. The apparent lack of RMU effect on parameter estimates within species may be an artifact of the small number of RMUs with published growth parameter estimates. The species-specific, and in some cases RMU-specific, posterior means and standard deviations of K and L∞ from this study would be appropriate priors for future studies of growth in chelonid sea turtles or for models of population dynamics. We highlight the need for expanded study and synthesis of sea turtle somatic growth rates.


Author(s):  
C.A. Carmona-Suárez

The decorator crab, Microphrys bicornutus, is a common inhabitant of the turtle grass Thalassia testudinum. In order to establish the behaviour of a population of this species in an extreme shallow Thalassia complex (maximum depth less than 50 cm, and often exposed to the air), size distribution, population dynamics, reproductive effort and egg size were studied in Buchuaco—Venezuela. Monthly sampling was undertaken between June 1988 and December 1990. A total of 1403 specimens of M. bicornutus were captured. In each of the sampled years, size distribution was strongly skewed to the predominance of small size crabs. Females were significantly larger than males in all the three years. Small size and large size crabs showed periodic annual fluctuations in abundance, with peaks during the last months of the year for the first, and peaks between April and June for the latter. Medium size crabs showed no periodicity at all. Number of eggs per female ranged between 40 and 4305 (mean = 1067.4), and was positively correlated with female body size. Eggs increased their size gradually during their development, and differences in egg size between development stages were significant. The biological parameters found in this study are compared with other populations of this crab, found in Venezuela and Brazil, in different ecosystems. Results acquired in this work add new insights to the behaviour of this decorator crab, specifically on density variation and egg size (among others), living in an environment that is constantly exposed to air and to other physicochemical variations.


This chapter demonstrates the application of state- and prediction-based theory (SPT) to a real biological system, but a system that has been simplified enough to also be addressed by dynamic state variable modeling (DSVM). The Daphnia vertical migration (VM) system allows one to explore ways to use SPT for an adaptive trade-off behavior that clearly is important to population dynamics, and to compare the behavior it produces to behavior predicted by a DSVM model and observed in real organisms. The chapter reproduces the three patterns of observed behavior, in almost all their details, while converting Øyvind Fiksen's DSVM model into a population model that includes mortality and reproduction and could easily include processes that make DSVM intractable—like interaction and variation among individuals. One lesson is that SPT can readily represent contingent decisions, such as Daphnia choice of both depth and reproductive allocation. This is not surprising because such decisions have also been modeled with DSVM.


2008 ◽  
Vol 4 (2) ◽  
pp. 224-227 ◽  
Author(s):  
Katja U Heubel ◽  
Kai Lindström ◽  
Hanna Kokko

Trade-offs between current and future reproduction shape life histories of organisms, e.g. increased mortality selects for earlier reproductive effort, and mate limitation has been shown to shape male life histories. Here, we show that female life histories respond adaptively to mate limitation. Female common gobies ( Pomatoschistus microps ) respond to a female-biased operational sex ratio by strongly increasing the size of their first clutch. The plastic response is predicted by a model that assumes that females use the current competitive situation to predict future difficulties of securing a mating. Because female clutch size decisions are much more closely linked to population dynamics than male life-history traits, plastic responses to mate-finding limitations may be an underappreciated force in population dynamics.


2021 ◽  
Vol 16 (4) ◽  
pp. 327-336
Author(s):  
MUHAMMAD AFIQ AHMAD KHAIRUDDIN ◽  
UMMU ATIQAH MOHD ROSLAN ◽  
HAMIZAH MOHD SAFUAN ◽  
MOHD UZAIR RUSLI ◽  

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